Exploratory insights into novel prehabilitative neuromuscular exercise-conditioning in total knee arthroplasty.

BACKGROUND: Contemporary strategies for prehabilitation and rehabilitation associated with total knee arthroplasty (TKA) surgery have focused on improving joint range-of-motion and function with less emphasis on neuromuscular performance beneficially affecting joint stability. Furthermore, prehabilitation protocols have been found to be too long and generic-in-effect to be considered suitable for routine clinical practice. METHODS: A pragmatic exploratory controlled trial was designed to investigate the efficacy of a novel, acute prehabilitative neuromuscular exercise-conditioning (APNEC) in patients electing TKA. Adults electing unilateral TKA were assessed and randomly allocated to exercise-conditioning (APNEC, n = 15) and usual care (Control, n = 14) from a specialised orthopaedic hospital, in the United Kingdom. APNEC prescribed nine stressful exercise-conditioning sessions for the knee extensors of the surgery leg, accrued over one week (3 sessions·week-1; 36 exercise repetitions in total; machine, gravity-loaded) and directly compared with usual care (no exercise). Prescribed exercise stress ranged between 60%-100% of participant's daily voluntary strength capacity, encompassing purposefully brief muscular activations (≤ 1.5 s). Baseline and follow-up indices of neuromuscular performance focusing on muscle activation capacity (electromechanical delay [EMD], rate of force development [RFD] and peak force [PF]) were measured ipsilaterally using dynamometry and concomitant surface electromyography (m. rectus femoris[RF] and m. vastus lateralis[VL]). RESULTS: Group mean ipsilateral knee extensor muscular activation capacity (EMDRF [F(3,57) = 53.5; p < 0.001]; EMDVL [F(3,57) = 50.0; p < 0.001]; RFD [F(3,57) = 10.5; p < 0.001]) and strength (PF [F(3,57) = 16.4; p < 0.001]) were significantly increased following APNEC (Cohen's d, 0.5-1.8; 15% to 36% vs. baseline), but unchanged following no exercise control (per protocol, group by time interaction, factorial ANOVA, with repeated measures), with significant retention of gains at 1-week follow-up (p < 0.001). CONCLUSIONS: The exploratory APNEC protocol elicited significant and clinically-relevant improvement and its retention in neuromuscular performance in patients awaiting TKA. TRIAL REGISTRATION: (date and number): clinicaltrial.gov: NCT03113032 (4/04/2017) and ISRCTN75779521 (3/5/2017).

Hydrological intermittency drives diversity decline and functional homogenization in benthic diatom communities.

Over the last decades, the combined effects of global climate changes and severe land use modifications have been exacerbating river hydrological alterations and habitat fragmentation in many Mediterranean rivers. This trend is predicted to intensify, with expected significant impacts on taxonomic and functional diversity of benthic communities in the next future. By comparing perennial and intermittent reaches, the present research aims at investigating the role of flow intermittency, driven by the combined effects of climatic variables and land use changes, on benthic diatom communities in Mediterranean streams (NW Italy), by analysing data collected over 11 years. In order to avoid potential confounding effects related to water quality, sites characterized by "poor" or "bad" water quality were excluded a priori. We observed significant differences between permanent and intermittent sections in terms of both climatic variables and land use: higher temperatures and lower precipitations, coupled with an extensive anthropic land use, intensify the natural flow intermittency in intermittent sites. This led to a significant decline in diatom species diversity, at both local and regional scales, and to changes to life history traits. In particular, communities of intermittent reaches were taxonomically and functionally different and less heterogeneous than assemblages characterizing perennial ones, showing higher percentages of small, mainly stalked and pioneer taxa belonging to the low profile guild. Conversely taxa colonizing permanent reaches were bigger, belonging to the high profile guild and able to produce colonies, thus indicating high environmental stability. Our results highlighted how hydrological alterations are profoundly threatening Mediterranean streams and the diatom communities inhabiting them, therefore representing an important benchmark in view of the improvement of biological indices for the assessment of intermittent rivers.